Enfold WP Theme: Dummy data import continues to fail

Dear Support
I purchased your Enfold WP theme some time ago and have been trying to set up the new website today for the purpose of which I had bought the theme. However, as apparently already experienced by other users, I continue to receive an error message when I try to import the dummy data. Only some marginal comments and postings seem to be imported. Googling the problem, I noted several threads in your support forum related to this issue and already have tried to implement solutions offered therein, so far without any successes. Here is what happened:

1. Attempt no. 1:
Fresh installation of wordpress 3.9.1 and creation of new mysql databank
installation of the theme (version 2.7)
activation of theme
import of dummy data (failed)
after googling tried to enhance memory by changing config.php – no success
Wordpress installations and mysql database were deleted

2. Attempt no. 2:
Fresh installation of wordpress 3.9.1 and creation of new mysql databank
installation of the theme (version 2.7)
activation of theme
update of the theme (version 2.9)
import of dummy data (failed)
enhancing of memory by changing config.php – no success
Wordpress installations and mysql database were deleted

3. Attempt no. 3:
Fresh installation of wordpress 3.9.1 and creation of new mysql databank
installation of the theme (version 2.7)
use of different browser (now opera instead of firefox)
activation of theme
update of the theme (version 2.9)
import of dummy data (failed)
Wordpress installations and mysql database were deleted

* * *

In none of the cases any plugins had been activated. I am running out of ideas and need some advice from professional side. If nothing will help I see no other solution than approaching Themeforest for a refund…
Regards
Christoph